Constraint-Induced Movement Therapy Promotes Neural Remodeling and Functional Reorganization by Overcoming Nogo-A/NgR/RhoA/ROCK Signals in Hemiplegic Cerebral Palsy Mice

Constraint-Induced Movement Therapy Promotes Myelin Remodeling and Motor Function by Mediating Sox2/Fyn Signals in Rats With Hemiplegic Cerebral Palsy

OBJECTIVE

Hypoxic-ischemic brain injury in infants often leads to hemiplegic motor dysfunction. The mechanism of their motor dysfunction has been attributed to deficiencies of the transcription factor sex-determining region (SRY) box 2 (Sox2) or the non-receptor-type tyrosine kinase Fyn (involved in neuronal signal transduction), which causes a defect in myelin formation. Constraint-induced movement therapy (CIMT) following cerebral hypoxia-ischemia may stimulate myelin growth by regulating Sox2/Fyn, Ras homolog protein family A (RhoA), and rho-associated kinase 2 (ROCK2) expression levels. This study investigated how Sox2/Fyn regulates myelin remodeling following CIMT to improve motor function in rats with hemiplegic cerebral palsy (HCP).

METHODS

To investigate the mechanism of Sox2 involvement in myelin growth and neural function in rats with HCP, Lentivirus (Lenti)-Sox2 adeno-associated virus and negative control-Lenti-Sox2 (LS) adeno-associated virus were injected into the lateral ventricle. The rats were divided into a control group and an HCP group with different interventions (CIMT, LS, or negative control-LS [NS] treatment), yielding the HCP, HCP plus CIMT (HCP + CIMT), HCP + LS, HCP + LS + CIMT, HCP + NS, and HCP + NS + CIMT groups. Front-limb suspension and RotaRod tests, Golgi-Cox staining, transmission electron microscopy, immunofluorescence staining, western blotting, and quantitative polymerase chain reaction experiments were used to analyze the motor function, dendrite/axon area, myelin ultrastructure, and levels of expression of oligodendrocytes and Sox2/Fyn/RhoA/ROCK2 in the motor cortex.

RESULTS

The rats in the HCP + LS + CIMT group had better values for motor function, dendrite/axon area, myelin ultrastructure, oligodendrocytes, and Sox2/Fyn/RhoA/ROCK2 expression in the motor cortex than rats in the HCP and HCP + NS groups. The improvement of motor function and myelin remodeling, the expression of oligodendrocytes, and the expression of Sox2/Fyn/RhoA/ROCK2 in the HCP + LS group were similar to those in the HCP + CIMT group.

CONCLUSION

CIMT might overcome RhoA/ROCK2 signaling by upregulating the transcription of Sox2 to Fyn in the brain to induce the maturation and differentiation of oligodendrocytes, thereby promoting myelin remodeling and improving motor function in rats with HCP.

IMPACT

The pathway mediated by Sox2/Fyn could be a promising therapeutic target for HCP.

Constraint therapy promotes motor cortex remodeling and functional improvement by regulating c-Jun/miR-182-5p/Nogo - A signals in hemiplegic cerebral palsy mice

BACKGROUND

Our previous study has confirmed that constraint-induced movement therapy (CIMT) could promote neural remodeling in hemiplegic cerebral palsy (HCP) mice through Nogo-A/NgR/RhoA/ROCK signaling, however, the upstream mechanism was still unclear. Therefore, the present study aimed to further explore the mechanism of CIMT regulating the expression of Nogo-A in HCP mice.

METHOD

HCP mice were well established through ligating the left common carotid artery of 7-day-old pups and being placed in a hypoxic box which was filled with a mixture of 8% oxygen and 92% nitrogen. CIMT intervention was conducted by taping to fix the entire arm of the contralateral side (left) to force the mice to use the affected limb (right). Bioinformatics prediction and luciferase experiment were performed to confirm that miR-182-5p was targeted with Nogo-A. The beam test and grip test were applied to examine the behavioral performance under the intervention of c-Jun and CIMT. Also, immunofluorescence, Golgi staining, and transmission electron microscopy were conducted to show that the lenti-expression of c-Jun could increases the expression of myelin, and downregulates the expression of Nogo-A under the CIMT on HCP mice.

RESULT

(1) The beam walking test and grip test experiment results showed that compared with the control group, the HCP + nCIMT group's forelimb grasping ability and balance coordination ability were decreased (P < 0.05). (2) The results of Golgi staining, and transmission electron microscopy showed that the thickness of myelin sheath and the density of dendritic spines in the HCP + nCIMT group were lower than those in the control group (P < 0.05). Compared with the HCP + nCIMT group, the cerebral cortex myelin sheath thickness, dendrite spine density and nerve filament expression were increased in HCP + CIMT group (P < 0.05). (3) Immunofluorescence staining showed that the expression of Nogo-A in the cerebral cortex of the HCP + nCIMT group was higher than that of the HCP + CIMT group (P < 0.05). Compared with the HCP + CIMT group, the expression of Nogo-A in the HCP + LC + CIMT group was decreased and, in the HCP, + SC + CIMT group was significantly increased (P < 0.05). Compared with the HCP + nCIMT group, the expression of c-Jun in the control, HCP + CIMT, HCP + LC + nCIMT and HCP + LC + CIMT groups was significantly increased, and in the HCP + SC + CIMT was decreased (P < 0.05). (4) Real-time quantitative polymerase chain reaction (RT-qPCR) results showed that the expression level of miR-182-5p in the HCP + LC + CIMT group was more increased than that in the HCP + nCIMT group (P < 0.05). The expression level of miR-182-5p in the HCP + LC + CIMT group was higher than that in the HCP + LC + nCIMT group and the HCP + SC + CIMT group (P < 0.05).

CONCLUSION

These data identified that CIMT might stimulate the remodeling of neurons and myelin in the motor cortex by partially inhibiting the c-Jun/miR-182-5p/Nogo-A pathway, thereby facilitating the grasping performance and balance function of HCP mice.

Potential optimized route for mesenchymal stem cell transplantation in a rat model of cerebral palsy

Cerebral palsy (CP) is a movement and posture disorder that affects over 50 million people worldwide. Human umbilical cord-derived mesenchymal stem cell (hUC-MSC) transplantation has emerged as an attractive therapeutic strategy for CP. The administration route appears to be crucial for hUC-MSC to provide adequate neuroprotection. Wistar rats were given hypoxia-ischemia to make the CP model on postnatal day 5. On postnatal day 21, DiR-labeled hUC-MSC were transplanted into the CP rats by intravenous, intrathecal, and lateral ventricle for cell tracking. Uninfused CP rats served as the negative control. The motor behavioral and pathological alteration was analyzed 11, 25, and 39 days after transplantation to assess motor function, immune inflammation, neurotrophy, and endogenous repair. In vivo imaging tracking techniques revealed that intravenous infusion resulted in fewer transplanted cells in the target brain than intrathecal and lateral ventricle infusion (p＜0.05). Three different routes of hUC-MSC infusion improved the motor function of CP rats (p＜0.05). At 11 days post-infusion, intrathecal infusion outperformed intravenous with a significant neurotrophic and oligodendrocyte maturation effect (p＜0.05). Intrathecal infusion equaled lateral ventricle infusion after 25 days. At 39 days post-infusion, lateral ventricle infusion exceeded intravenous and intrathecal infusion with a significant immunosuppressive effect (p＜0.05). Considering the improved effect and less trauma shown early in the intrathecal infusion, repeated intrathecal administration may ultimately lead to the greatest benefit.

Proteomic changes of the bilateral M1 and spinal cord in hemiplegic cerebral palsy mouse: Effects of constraint-induced movement therapy

Hemiplegic cerebral palsy (HCP) is a non-progressive movement and posture disorder that affects one side of the body. Constraint-induced movement therapy (CIMT) can improve the hand function of children with HCP. We used label-free proteomic quantification technology to evaluate proteomic changes in the bilateral M1 and spinal cord in HCP mouse induced by hypoxia/ischemia and CIMT. Nissl staining showed reduced neuron density in the HCP mice's lesioned and contralesional M1. The rotarod test and grip strength test showed motor dysfunction in mice with HCP and improved motor ability after CIMT. A total of 5147 proteins were identified. Fifty-one, five, and sixty common differentially expressed proteins (DEPs), which were co-regulated by HCP and CIMT, were found in the lesioned M1, the contralesional M1 and the spinal cord respectively. The significant proteins included alpha-centractin, metaxin complex, PKC, septin 11, choline transporter-like proteins, protein 4.1, teneurin-4, and so on, which mainly related to synapse stability, neuronal development and maintenance, axon development, and myelin formation. The KEGG pathways of HCP-induced DEPs mainly related to lipid metabolism, synaptic remodeling, SNARE interactions in vesicular transport and axon formation. The CIMT-induced DEPs were mainly related to synaptic remodeling and axon formation in the lesioned M1 and spinal cord. This study investigated the proteomic changes of the bilateral M1 and spinal cord as well as the CIMT-induced proteomic changes in HCP mice, which might provide new insights into the therapy of HCP.

The Effect of Constraint-Induced Movement Therapy Combined With Repetitive Transcranial Magnetic Stimulation on Hand Function in Preschool Children With Unilateral Cerebral Palsy: A Randomized Controlled Preliminary Study

Constraint-induced movement therapy (CIMT) combined with repetitive transcranial magnetic stimulation (rTMS) have shown great potential in improving function in schoolchildren with unilateral cerebral palsy attributed to perinatal stroke. However, the prospect of application in preschool children with unilateral cerebral palsy (UCP) attributed to various brain disorders remains unclear. In this prospective, assessor-blinded, randomized controlled study, 40 preschool children with UCP (aged 2.5–6 years) were randomized to receive 10 days of CIMT combined with active or sham rTMS. Assessments were performed at baseline, 2 weeks, and 6 months post-intervention to investigate upper limb extremity, social life ability, and perceived changes by parents and motor-evoked potentials. Overall, 35 participants completed the trial. The CIMT plus active stimulation group had greater gains in the affected hand function (range of motion, accuracy, and fluency) than the CIMT plus sham stimulation group (P &lt; 0.05), but there was no significant difference in muscular tone, social life ability, and perceived changes by parents between the two groups (P &gt; 0.05). In addition, there was no significant difference in hand function between children with and without motor-evoked potential (P &gt; 0.05). No participants reported severe adverse events during the study session. In short, the treatment of CIMT combined with rTMS is safe and feasible for preschool children with UCP attributed to various brain disorders. Randomized controlled studies with large samples and long-term effects are warranted.